The invention relates to a method for controlling a wiping-washing process of a rear window cleaning system of a motor vehicle, which vehicle has at least one front windshield cleaning system and a headlight cleaning system for the headlights of the motor vehicle.
It is basically already known that the rear window wiper can be activated automatically as a function of the actuation of the front windshield wiper. For example, DE 196 39 137 A1 discloses a control device for a front windshield wiper and rear window wiper, wherein the rear window wiper is actuated automatically, inter alia, in such a way that the wiping frequency ratio or the duty cycle between the front windshield wiper and the rear window wiper is predefined.
The wiping-washing process of the rear window cleaning system is, however, basically triggered by manual activation. This entails increased effort for the driver, in particular in winter, since at this time of year an increased occurrence of dirt and road grit are to be expected, leading to heavier soiling of the rear window.
The object of the invention is then to provide a simple and convenient method, as well as a corresponding device, for influencing the control, in particular for automatically triggering a wiping-washing process, of a rear window wiper of a motor vehicle.
This and other objects are achieved by a method according to embodiments of the invention. The method and the advantageous refinements thereof can be carried out by way of an implemented algorithm or a corresponding assembly arrangement in a control device provided for that purpose.
The invention is based on the realization that at present there are already many vehicles on the market which have not only a front windshield wiper and a rear window wiper, but also a front windshield cleaning system and a headlight cleaning system for the headlights of the motor vehicle. The operator control of a headlight cleaning system is often different depending on the vehicle manufacturer and year of construction of the vehicle. The headlight cleaning systems can be activated automatically in this context, as soon as the front windshield washing system is activated when the dipped headlights are switched on, while other systems have a separate switch for manually triggering the headlight cleaning process. In vehicles which are equipped with xenon headlights, a headlight cleaning system is even legally required.
The method according to the invention is defined by the fact that the wiping-washing process of the rear window cleaning system is controlled or influenced as a function of the actuation of the headlight cleaning system and/or of the front windshield cleaning system, in particular in such a way that the wiping-washing process of the rear window cleaning system is triggered as a function of the actuation of the headlight cleaning system and/or of the front windshield cleaning system. In other words, the triggering and also the type of wiping-washing process of the rear window wiper is influenced or controlled as a function of the actuation, in particular as a function of the triggering or triggering time, of the headlight washing process of the headlights or of the front windshield cleaning system.
The triggering of the wiping-washing process of the rear window cleaning system is advantageously influenced by the actuation or the operation of the headlight cleaning system in such a way that the wiping-washing process of the rear window cleaning system is triggered at the latest, but advantageously simultaneously with, the triggering of the headlight cleaning process of the headlight cleaning system. This means that the wiping-washing process is therefore triggered automatically at the latest when the headlights are cleaned.
Alternatively or additionally, the triggering of the wiping-washing process of the rear window wiper can also be influenced by the actuation or the operation of the headlight cleaning system in such a way that the wiping-washing process of the rear window cleaning system is triggered with a predefined first duty cycle with respect to the headlight cleaning process of the headlight cleaning system. It is therefore possible, for example, for the wiping-washing process to be triggered every second time after the headlight cleaning process has been triggered, i.e. the predefined duty cycle between the wiping-washing process of the rear window cleaning system and the headlight cleaning process of the headlight cleaning system would be 1:2.
Alternatively, the first duty cycle could also be predefined in such a way that two wiping-washing processes of the rear window cleaning system occur between two headlight cleaning processes, the predefined first duty cycle between the wiping-washing process of the rear window cleaning system and the headlight cleaning process of the headlight cleaning system would then be 2:1. Such a first duty cycle in which the wiping-washing frequency of the rear window cleaning system is lower than the wiping-washing frequency of the headlight cleaning system presumes that a certain estimation of the time of the next wiping-washing process of the headlight cleaning system is possible.
This can be made possible, for example, if the actuation of the headlight cleaning system and/or of the headlight cleaning process is triggered as a function of the actuation of the front windshield wiper and/or as a function of the actuation of the front windshield cleaning system. It can be defined, for example, that the duty cycle between the front windshield washing process and headlight cleaning process is 10:1. If 1:2 is then predefined as the first duty cycle between the headlight cleaning process and the wiping-washing process of the rear window, this results in a duty cycle between the front windshield washing process and the wiping-washing process of the rear window cleaning system of 1:5.
Analogously to this, the triggering of the wiping-washing process of the rear window wiper can also be influenced by the actuation or the operation of the front windshield cleaning system, in particular in such a way that the wiping-washing process of the rear window cleaning system is triggered with a predefined second duty cycle with respect to the wiping-washing process of the front windshield cleaning system.
The triggering or the type of the wiping-washing process of the rear window cleaning system can also advantageously be influenced by the operation of the rear window heater.
According to an alternative, the rear window heater can be taken into consideration here in such a way that when the rear window heater is active the wiping-washing process of the rear window cleaning system is triggered with a predefined third duty cycle with respect to the headlight cleaning process of the headlight cleaning system or with a predefined fourth duty cycle with respect to the wiping-washing process of the front windshield cleaning system, and/or the quantity of washing water is changed, in particular increased, during the wiping-washing process.
This refinement is therefore advantageous since in the case of an active rear window heater there is a high probability that it is the winter and increased occurrence of dirt and road grit is to be expected during this time. If, when the rear window heater is active, the duty cycle between the headlight cleaning process of the headlight cleaning system and the wiping-washing process of the rear window cleaning system is changed in such a way that the frequency of the wiping-washing process of the rear window cleaning system is increased compared to the frequency of the headlight cleaning process, better cleaning of the rear window can be achieved. Additionally or alternatively, when the rear window heater is active it is also possible to change the quantity of water that is used during the wiping-washing process of the rear window, in particular to increase it, in order thereby to cope with the increased occurrence of dirt.
Likewise, the wiping-washing process of the rear window cleaning system can also be influenced as a function of the operation of the rear window heater such that the (automatic) wiping-washing process of the rear window cleaning system is influenced or triggered as a function of the actuation of the headlight cleaning system, in particular as a function of the triggered headlight cleaning process, only if the rear window heater is operating. The automatic association of the wiping-washing process of the rear window with the headlight cleaning process and the automatic triggering of the wiping-washing process of the rear window on the basis of the headlight cleaning process would therefore take place only in the winter operating mode.
A further parameter for increasing the triggering accuracy of the wiping-washing cycle can occur technically by measuring the current of the rear window heater. By taking into account this realization, the method according to the invention can therefore be developed in such a way that the wiping-washing process of the rear window cleaning system is triggered or influenced as a function of the flow of current through the rear window heater, in particular in such a way that the wiping-washing process of the rear window cleaning system is triggered with a predefined fifth duty cycle with respect to the headlight cleaning process of the headlight cleaning system, and/or the quantity of washing water during the wiping-washing process is changed, as a function of the flow of current through the rear window heater.
Since triggering of the wiping-washing process of the rear window cleaning system can be considered to be more or less appropriate depending on the iced-up state of the rear window, the wiping-washing process of the rear window wiper can also be triggered or influenced as a function of the detected or assumed iced-up state of the rear window, wherein the iced-up state and/or the degree of the iced-up state of the rear window can advantageously be determined by evaluating the calculated or measured starting current of the rear window wiper motor.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.